Can't figure out how to crop header photo. Need to switch premium templates.

Two things. I can load the image I want into the header, but it is cropped incorrectly. I would like to crop it manually and cannot. Also, I purchased a premium template (Linen) but would like to switch to Elemin.
Blog url: http://verticalviv.wordpress.com

For future reference, there will be a link for the specific Premium Theme support forum under Appearance -> Themes in your blog’s Dashboard, but the theme needs to be active and you need to be signed in as the user who purchased it in order to see it.